Foldable product with fold lines that are partly provided with creases and partly by lines of perforations

ABSTRACT

There is provided a foldable product, such as a map, which is formed from a sheet ( 10 ) of material such as stiff paper. The sheet ( 10 ) has predetemlined folded and unfolded configurations by virtue of a predetermined pattern of fold lines ( 12, 13, 14, 19, 20, 23, 24 ). The fold lines are provided partly by creases and partly by lines of perforations depending on the stress in a particular area during folding and unfolding.

[0001] The present invention relates to a foldable product formed from asheet of material adapted to be unfolded and folded repeatedly duringuse simply by opening and closing a cover, and is concerned inparticular but not exclusively with a foldable map.

[0002] It is known to provide many forms of foldable products of sheetmaterial such as stiff paper which require to be folded and unfoldedrepeatedly in use, for example foldable maps. Commonly in a simple formof foldable map, the map is rectangular, and is folded along one or morelongitudinal fold lines extending along the length of the map, and thenis cross-folded across one or more transverse fold lines, which aretransverse to the length of the map. The present invention isparticularly, but exclusively, concerned with a more complicated form offolding map, known as a star-folded map, where a series of inward andoutward folds are made, principally along fold lines meeting at a centrepoint of the sheet, but also including secondary fold lines positionedtowards the edges of the sheets. The arrangement is such that when themap is folded to a predetermined folded condition, two principalportions of the sheet are closed one onto the other by a closingmovement in the manner of the closing of the covers of a book, and otherportions of the map are automatically folded inwardly so as to beenclosed between the two closed principal portions of the sheet. In thisway the map may be folded to an area much smaller than the open map, andcan be folded by a single closing movement similar to closing the coversof a book. An example of such a star-folded map sheet is disclosed inU.S. Pat. No. 4,636,192.

[0003] In manufacturing a foldable product such as a star-folded map thesheet is provided with a predetermined pattern of fold lines definingthe lines along which the product is to be folded. Traditionally this isdone by providing simple score or crease lines on the sheet. After thefold lines have been formed on the sheet, the product is folded for thefirst time, either manually or by machine, to produce the commercialproduct. However simple scoring or creasing of the fold lines oftenresults in significantly less precise fold lines than are commerciallyacceptable, as well as requiring a long production finishing time due tothe requirement of ensuring the fold line is pressed completely flat. Ifthe score or crease line is not finished flat with a sharp edge, thepaper fold tends to collapse along the line, resulting in a damage tothe paper when the cover is closed.

[0004] An alternative which is used sometimes is to perforate along theentire fold line. While this enables a more accurate fold to be obtainedas will the use of a thicker paper, a disadvantage arises as theperforated line will often split due to significant stress occurring asthe paper sheet is opened.

[0005] It is an object of the present invention to provide an improvedfoldable product which eliminates or reduces the problem of paper tearby perforation, and enables a faster production time than is provided byscoring or creasing the paper.

[0006] According to the present invention there is provided a foldableproduct formed from a sheet of material, comprising: a sheet of materialadapted to be folded and unfolded repeatedly during use between apredetermined folded configuration and a predetermined unfoldedconfiguration, the sheet bearing a predetermined pattern of fold linesdefining the lines along which the product is to be folded, in which thefold lines are partly provided by creases and partly by lines ofperforations, the creases being positioned at locations subject togreater stress during folding and unfolding of the product.

[0007] In preferred arrangements of the present invention, at least someof the fold lines radiate outwardly from a generally central point ofthe sheet, and each outwardly radiating fold line has a creased portionand a perforated portion, the creased portion being located at aproximal portion of the fold line, extending outwardly from the centralpoint. Also in preferred arrangements, at least some of the fold linesextend from an edge of the sheet, and each such fold line includes acreased portion and a perforated portion, the creased portion of thesaid extending fold line being located to extend from the said edge ofthe sheet along the fold line.

[0008] The invention finds particular application in a foldable productof the so-called star-folded form, in which the predetermined unfoldedconfiguration comprises the sheet lying substantially flat and thepredetermined folded configuration comprises two principal portions ofthe sheet being closed one onto the other by a closing movement about aprincipal axis of the sheet in the manner of closing the covers of abook. The fold lines of the sheet define inward and outward rectilinearfolds when the product is folded to the predetermined foldedconfiguration, the said inward folds extending inwardly relative to theclosure of the principal portions together, and the said outward foldsextending outwardly relative to the closure of the two principalportions together. The fold lines of the sheet define the fold lines ofthe sheet defining four principal outward folds meeting at a generallycentral point of the sheet and arranged as opposed pairs of outwardfolds, and two principal inward folds meeting at the central point ofthe sheet and arranged as an opposed pair of inward folds. Eachprincipal outward fold divides at its distal end into two edge outwardfolds which diverge from the direction of the associated principaloutward fold and extend to respective edges of the sheet. Each saiddistal end of a principal outward fold has an edge inward fold extendingtherefrom along the same direction as the direction of the associatedprincipal outward fold and extending to an edge of the sheet.

[0009] In such a star-folded product it is preferred that each fold linewhich defines a principal outward fold has a creased portion and aperforated portion, the creased portion extending from the centre (M)along the fold line and the perforated portion extending from the distalend of the principal outward fold along the fold line. Preferably thecreased portion of the fold line of the principal outward fold extendsalong a distance in the range 25% to 30% of the length of the principaloutward fold, preferably approximately 27%.

[0010] It is preferred that each fold line which defines a principalinward fold has two creased portions and a perforated portion, thecreased portion extending from the centre (M) along the fold line, thecreased portion extending from an edge of the sheet along the fold line,and the perforated portion extending along a middle portion of the foldline. Preferably the creased portion which extends from the edge of thesheet, extends along a distance in the range 3% to 6% of the length ofthe principal inward fold, preferably approximately 4%. It is alsopreferred that the creased portion of the fold line of the principalinward fold which extends from the central point of the sheet, extendsalong a distance in the range 10% to 15% of the length of the principalinward fold, preferably 11%.

[0011] It is also preferred that each fold line which defines an edgeoutward fold has a creased portion and a perforated, the creased portionextending from an edge of the sheet along the fold line and theperforated portion extending from the distal end of the principaloutward fold along the fold line. Preferably the creased portion of thefold line of the edge outward fold extends along a distance in the range5% to 15% of the length of the edge outward fold, preferablyapproximately 10%.

[0012] Furthermore it is preferred that each fold line which defines anedge inward fold has two creased portions and two perforated portions,one perforated portion extending from the centre distal end of theprincipal outward fold along the fold line, one creased portionextending from an edge of the sheet along the fold line, and the secondperforated portion and the second creased portion extending along amiddle portion of the fold line. Preferably the creased portion whichextends from the edge of the sheet, extends along a distance in therange 5% to 10% of the length of the edge inward fold, preferablyapproximately 8%. Also preferably the creased portion of the fold lineof the principal inward fold which extends from the central point of thesheet, extends along a distance in the range 10% to 15% of the length ofthe principal inward fold, preferably approximately 16%.

[0013] To summarise, overall it is preferred that in a star-folded formof foldable product embodying the invention, each creased portion ofeach fold line extends along a distance in the range 3% to 30% of thelength of the respective fold line.

[0014] It is to be appreciated that the invention may be applied to manyforms of foldable product, whether star-shaped or having folds allaligned to rectangular sides of a sheet. Also the outer perimeter of thesheet may be different from the conventional rectangular shape, and mayfor example be curved. However the invention has particular applicationin a star-folded foldable product of the kind set out, in which thesheet is substantially rectangular having one pair of opposed sideslonger than the other opposed pair of sides, the said principal axis ofthe sheet being positioned at right angles to the longer sides thereof,and the opposed pair of inward folds also being arranged at right anglesto the longer sides of the rectangle. In such an arrangement it ispreferred that each edge outward fold extends from its associated distalend point of the associated outward fold, to an associated edge of thesheet, at right angles to the associated edge. Also preferably eachprincipal outward fold extends outwardly from the centre point of thesheet in a direction subtending 45° to the next adjacent inward fold.

[0015] In general, the invention finds particular use where the sheethas an information bearing face on the side of the sheet facing inwardlyupon closure of the two principal portions of the sheet. In such aproduct, it may be arranged that portions of the other side of the sheetare secured to a backing sheet of material stiffer than the firstmentioned sheet, such that upon closure of the stiff outer sheet byfolding about the principal axis, the said principal portions arebrought together in the manner of a book, while other portions of thesheet are free to fold about the said fold lines in such a manner thatupon closure of the product the folded sheet is substantially entirelycontained within the folded stiff outer sheet within an areasubstantially equal to the said principal portions.

[0016] Embodiments of the invention, at least in preferred forms, may bearranged to provide a combination of the advantages of a known form offoldable product where the fold lines are entirely creased, and of knownforms of foldable product where the fold lines are entirely perforated.In accordance with the present invention, by selecting particularlocations in which the creased portions are provided, it is possible toprovide the combined advantages of the previous systems. The locationsof the creased or scored portions are determined by the areas of higherstress, where tearing is more likely to occur during repeated use of theproduct.

[0017] It is to be appreciated that the terms “creased fold line” and“scored fold line” are synonymous, and that both forms of fold line areencompassed by the use of the term “creased” in the presentspecification.

[0018] Embodiments of the invention will now be described by way ofexample with reference to the accompanying drawings in which:

[0019]FIG. 1 shows a sheet of material forming a foldable product ofknown form, the sheet being laid out in a predetermined unfoldedconfiguration, the sheet being perforated on the lines of the intendedfolds;

[0020]FIG. 2 shows the known foldable sheet of FIG. 1 when glued into acover sheet, and when partially moved from the unfolded configuration tothe folded configuration;

[0021]FIG. 3 is a plan view of the sheet of FIG. 1, when positionedmid-way between the unfolded and folded configuration; and

[0022]FIG. 4 is a perspective view of the folded sheet of the previousFigures, folded together with principal portions of the sheet lying oneon top of the other, viewed from the front; and

[0023]FIG. 5 is a plan view of a sheet of a foldable product,corresponding generally to the view of the prior art in FIG. 1, butembodying the present invention.

[0024] Referring firstly to FIGS. 1 to 4, there is shown a foldableproduct of the kind disclosed in U.S. Pat. No. 4,636,192. In this priordisclosure there is described, as shown particularly in FIG. 1, a sheet10 of stiffened paper or other suitable material, which is to be foldedto the shape of the area of the shaded area F, and to this end isprovided with outward and inward folds along fold lines indicated inFIG. 1.

[0025] Referring to FIG. 1, the sheet 10 bears a number of fold lineswhich are indicated by dotted lines and dashed lines, and are formed bya line of closely packed perforations or cuts in each case. Fold lineswhich give rise to inward folds are indicated by dotted lines, and foldlines which give rise to outward folds are indicated by dashed lines.The fold lines are such that inward and outward folds are formed suchthat the sheet can be folded together when two halves of the sheet 10,indicated at 10 a and 10 b, are folded together along a central axis. 11in the manner of a book. In this closing movement, two principalportions of the sheet, indicated at 9 a and 9 b, are folded one on topof the other, and the remaining parts of the sheet become foldedinwardly so as to be entirely folded within the area indicated by theshaded area F.

[0026] As shown in particular in FIGS. 1 and 2, the sheet 10 has at itscentre two principal inward folds 12 that extend in a directionindicated by X and meet at a generally central point M, and fourprincipal outward folds 13 and 14 which also meet at the centre point M.The principal outward folds 14, 14 are aligned opposite each other, at45° to the inward folds 12, 12, and the principal outward folds 13 aresimilarly aligned, and are at right angles to the outward folds 14. Theoutward folds 13 and 14 are directed approximately towards the cornersof the sheet and intersect its long edges 15 and 16 at a short distancefrom the corners.

[0027] Each principal outward fold 13, 14 divides at its distal end 17,18 into two edge outward folds 19, 20 which diverge from the directionof the associated principal outward fold 13, 14 and extend to respectiveedges of the sheet 10. Each distal end 17, 18 of a principal outwardfold 13, 14 has an edge inward fold 23, 24 extending therefrom along thesame direction as the direction of the associated principal outward fold13, 14. Each edge inward fold 23, 24 extends to an edge of the sheet 10,indicated at 15 or 16.

[0028] As shown in FIG. 2, the sheet 10 is secured to a stiff backing orbinding sheet 25 comprised of two halves which may be closed together inthe form of a book. The sheet 10 is attached to the backing sheet 25 atspaced apart portions located on the rear side of the principal portions9 a and 9 b of the sheet. Other areas of the sheet 10 are free to move,and in particular the centre point M is not secured to the backing sheet25, but is free to allow the inward movement of the inward folds 12during closure. FIG. 3 shows further movement of the foldable producttowards complete closure, and FIG. 4 shows complete closure of theproduct.

[0029] Referring now to FIG. 5, there is shown an embodiment of thepresent invention, which corresponds generally to the product shown inFIG. 1 of the known arrangement, except for the formation of the foldlines. Components and features which are common to the embodiment of thepresent invention in FIG. 5, and the known arrangement of FIG. 1, areindicated by like reference numerals. In FIG. 5, again inward folds areindicated by dotted lines and outward folds are indicated by dashedlines. However in FIG. 5, the dotted lines and dashed lines specificallyindicate perforations, and the fold lines further included solid lines,which indicate non-perforated creased or scored fold lines. In thediagrammatic representation of FIG. 5, the significance of the dottedand dashed lines is merely to indicate inward or outward perforatedfolds, and specifically does not indicate the density or shape of theperforations.

[0030] Considering the arrangement of FIG. 5 in detail, each fold linewhich defines a principal outward fold 13 has a creased portion 13 a anda perforated portion 13 b, the creased portion 13 a extending from thecentre M along the fold line towards an edge or corner of the sheet 10.The perforated portion 13 b extends from the end of the creased portion13 a, to the distal end 17 of the principal outward fold 13. Similarly,each principal outward fold 14 is composed of a creased portion 14 aleading from the centre M, and a perforated portion 14 b extending fromthe end of the creased portion 14 a to the distal end 18 of theprincipal outward fold 14.

[0031] Each fold line which defines a principal inward fold 12 has twocreased portions 12 a and 12 c and a perforated portion 12 b. Thecreased portion 12 c extends from the centre M along the fold line andthe creased portion 12 a extends from an edge 15 or 16 of the sheet 10along the fold line towards the centre M. The perforated portion 12 bextends along a middle portion of the fold line, joining the creasedportions 12 a and 12 c.

[0032] Each fold line which defines an edge outward fold 19 has acreased portion 19 a and a perforated portion 19 b, the creased portion19 a extending from an edge 22 of the sheet along the fold line and theperforated portion 19 b extending from the distal end 17 or 18 of theprincipal outward fold 13 or 14 along the fold line. Similar creased andperforated portions are provided at the other edge outward folds 20.

[0033] Each fold line which defines an edge inward fold 23 has twocreased portions 23 a and 23 c and two perforated portions 23 b and 23d. One perforated portion 23 d extends from the distal end 17 of theassociated principal outward fold 13 along the fold line. The creasedportion 13 a extends from an edge 15 or 16 of the sheet 10 along thefold line inwardly towards the centre M. The second perforated portion23 b and the second creased portion 23 c extend along a middle portionof the fold line, alternately with the creased and perforated portions23 a and 23 d.

[0034] Various exemplary dimensions of the product are shown on thedrawing labelled A to I, and may be as set out in the following table. A 5 mm B  26 mm C  38 mm D 215 mm E  64 mm F  25 mm G  81 mm H 125 mm I250 mm

[0035] As a generally preferred exemplary range for the creased portionsof the fold lines, it is preferred that each creased portion of eachfold line extends along a distance in the range 3% to 30% of the lengthof the respective fold line. Particularly preferred ranges and examplesof the proportions of the creased and perforated parts of the foldlines, may conveniently be as has been set out in the introduction ofthis specification.

[0036] The selection of the portions of the fold lines which are creasedor scored, in proportion to the extent of the fold lines which areperforated, is selected so that the creased or scored portions arepositioned at locations subject to greater stress during folding andunfolding of the product, that is to say areas which are found in theprior art examples to be most likely to allow tearing of the product.

[0037] Advantages of the embodiment of the invention shown, combiningperforated and scored or creased fold lines, include reducing the timerequired for producing the product, especially when produced manually,significantly reducing damage occurring to the product in use, andextending the usefulness and the effectiveness of the product, andfinally increasing the life of each folded product.

1. A foldable product formed from a sheet of material, comprising: asheet of material adapted to be folded and unfolded repeatedly duringuse between a predetermined folded configuration and a predeterminedunfolded configuration, the sheet bearing a predetermined pattern offold lines defining the lines along which the product is to be folded;in which the fold lines are partly provided by creases and partly bylines of perforations, the creases being positioned at locations subjectto greater stress during folding and unfolding of the product.
 2. Afoldable product according to claim 1, in which at least some of thefold lines radiate outwardly from a generally central point of thesheet, and each outwardly radiating fold line has a creased portion anda perforated portion, the creased portion being located at a proximalportion of the fold line, extending outwardly from the central point. 3.A product according to claim 1, in which at least some of the fold linesextend from an edge of the sheet, and each such fold line includes acreased portion and a perforated portion, the creased portion of thesaid extending fold line being located to extend from the said edge ofthe sheet along the fold line.
 4. A product according to claim 1, inwhich the predetermined unfolded configuration comprises the sheet lyingsubstantially flat and the predetermined folded configuration comprisestwo principal portions of the sheet being closed one onto the other by aclosing movement about a principal axis of the sheet in the manner ofclosing the covers of a book; the fold lines of the sheet defininginward and outward rectilinear folds when the product is folded to thepredetermined folded configuration, the said inward folds extendinginwardly relative to the closure of the principal portions together, andthe said outward folds extending outwardly relative to the closure ofthe two principal portions together; the fold lines of the sheetdefining four principal outward folds meeting at a generally centralpoint of the sheet and arranged as opposed pairs of outward folds, andtwo principal inward folds meeting at the central point of the sheet andarranged as an opposed pair of inward folds; each principal outward folddividing at its distal end into two edge outward folds which divergefrom the direction of the associated principal outward fold and extendto respective edges of the sheet; and each said distal end of aprincipal outward fold having a edge inward fold extending therefromalong the same direction as the direction of the associated principaloutward fold and extending to an edge of the sheet.
 5. A productaccording to claim 4, in which each fold line which defines a principaloutward fold has a creased portion and a perforated portion, the creasedportion extending from the centre along the fold line and the perforatedportion extending from the distal end of the principal outward foldalong the fold line.
 6. A product according to claim 5, in which thecreased portion of the fold line of the principal outward fold extendsalong a distance in the range 25% to 30% of the length of the principaloutward fold.
 7. A product according to claim 4, in which each fold linewhich defines a principal inward fold has two creased portions and aperforated portion, the creased portion extending from the centre alongthe fold line, the creased portion extending from an edge of the sheetalong the fold line, and the perforated portion extending along a middleportion of the fold line.
 8. A product according to claim 3, in whichthe creased portion which extends from the edge of the sheet, extendsalong a distance in the range 3% to 6% of the length of the principalinward fold.
 9. A product according to claim 7, in which the creasedportion of the fold line of the principal inward fold which extends fromthe central point of the sheet, extends along a distance in the range10% to 15% of the length of the principal inward fold.
 10. A productaccording to claim 4, in which each fold line which defines an edgeoutward fold has a creased portion and a perforated, the creased portionextending from an edge of the sheet along the fold line and theperforated portion extending from the distal end of the principaloutward fold along the fold line.
 11. A product according to claim 10,in which the creased portion of the fold line of the edge outward foldextends along a distance in the range 5% to 15% of the length of theedge outward fold.
 12. A product according to claim 4, in which eachfold line which defines an edge inward fold has two creased portions andtwo perforated portions, one perforated portion extending from thecentre distal end of the principal outward fold along the fold line, onecreased portion extending from an edge of the sheet along the fold line,and the second perforated portion and the second creased portionextending along a middle portion of the fold line.
 13. A productaccording to claim 12, in which the creased portion which extends fromthe edge of the sheet, extends along a distance in the range 5% to 10%of the length of the edge inward fold.
 14. A product according to claim12, in which the second creased portion of the fold line of the edgeinward fold extends along a distance in the range 10% to 20% of thelength of the edge inward fold.
 15. A product according to claim 5, inwhich each creased portion of each fold line extends along a distance inthe range 3% to 30% of the length of the respective fold line.
 16. Aproduct according to claim 4, in which the sheet is substantiallyrectangular having one pair of opposed sides longer than the otheropposed pair of sides, the said principal axis of the sheet beingpositioned at right angles to the longer sides thereof, and the opposedpair of inward folds also being arranged at right angles to the longersides of the rectangle.
 17. A product according to claim 16, in whicheach edge outward fold extends from its associated distal end point ofthe associated outward fold, to an associated edge of the sheet, atright angles to the associated edge.
 18. A product according to claim16, in which each principal outward fold extends outwardly from thecentre point of the sheet in a direction subtending 45° to the nextadjacent inward fold.
 19. A product according to claim 1, in which thesheet has an information bearing face on the side of the sheet facinginwardly upon closure of the two principal portions of the sheet.
 20. Aproduct according to claim 19, in which portions of the other side ofthe sheet are secured to a backing sheet of material stiffer than thefirst mentioned sheet, such that upon closure of the stiff outer sheetby folding about the principal axis, the said principal portions arebrought together in the manner of a book, while other portions of thesheet are free to fold about the said fold lines in such a manner thatupon closure of the product the folded sheet is substantially entirelycontained within the folded stiff outer sheet within an areasubstantially equal to the said principal portions.
 21. A productaccording to claim 19, in which the said information bearing surfacecomprises a map.
 22. A foldable product substantially as hereinbeforedescribed with reference to FIG. 5 of the accompanying drawings.